In a stringed instrument, each string is extended with a predetermined tension between two critical contact points that primarily define the effective length of the string. The first critical contact point is generally at the bridge, which is provided on the body of the instrument. The second critical contact point is generally at the nut which, depending on the instrument, is usually positioned on the head or at a point of the neck distant from the body of the instrument. Both the tension and the effective length of the string determine its musical tone.
The distance between the bridge and the nut is the primary determinant of the effective length of a string. However, an instrumentalist can shorten the effective length during a musical performance, by depressing the string with a finger until it contacts any one of a plurality of frets that are positioned along the neck of the instrument between the nut and the bridge.
Vibrating the string generates a musical tone. In an instrument such as a guitar, a musical tone is conventionally obtained by plucking the string with a finger; in an instrument such as a violin, the musical tone is obtained by drawing a bow back and forth across the string.
A string that is extended with an improper tension and is extended for a distance of an improper string length may result in a generation of a musical tone of an incorrect sound frequency. Accordingly, each of the strings specially needs to be extended under a proper tuning state.